——2X-6Y=7 Y=?2x-6y=7求y=?

{6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) ——2X-6Y=7 Y=?2x-6y=7求y=? x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 3x+5y-(x+y)=6 2(x+y)-3x=-7 把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)= 3(x-y)把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)=3(x-y)²-4(x-y)+7(x-y)-6(x-y)²= 若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值 求f(x,y)=x+y+7的最大值,使(x,y)满足x+2y≤10,2x+y≥6,y≥0 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 把(x-y)看做一个整体,合并同类项5(x-y)+2(x-y)-4(x-y)=3(x-y)次方-4(x-y)+7(x-y)-6(x-y)次方= [(2x—y)(2x+y)—y(y—6x)]除以2x=多少 3(x+y)—4(x—y)=4 { (x+y)/2+(x—y)/6=1 2(x-y)/3—x+y/4=1 6(x+y)—4(2x-y)=16 3(x+y)—4(x-y)=4,(x+y/2)+(x-y/6)=1.解方程组 y-x/7-x+y/6=1/2 5(x+y)-2(y-x)=1怎么解答 2(x+y)-3(x-y)=1 6(x+y)+7(x-y)=51 解方程组 解方程组﹛2(x+y)-3(x-y)=1 6(x+y)+7(x-y)=51